Field of the Invention
The present invention relates to a film forming apparatus for forming a film on a substrate by generating a plasma, and also relates to a method of manufacturing a semiconductor device.
Background Art
Both plasma enhanced atomic layer deposition (PEALD) and plasma chemical vapor deposition (plasma CVD) are film forming methods for forming a film by generating a plasma in a material gas. U.S. Pat. No. 5,366,585 discloses a film forming apparatus having a plasma reactor chamber.
Film forming apparatuses using a plasma include an insulator disposed so that the electrode for receiving power for generating a plasma is insulated from the surrounding components. In some film forming apparatuses, this insulator is exposed to the material gas flow path in the chamber. In such film forming apparatuses, formation of a metal film on a substrate, etc. in the chamber is accompanied by formation of a metal film on the insulator, during which the impedance of the plasma varies, resulting in unstable film forming operation. Further, when an insulating film is formed in the film forming apparatuses, a potential difference in the insulator causes generation of a plasma in the material gas flow path, also resulting in unstable film forming operation.